Shock absorber

ABSTRACT

A shock absorber including: a first cylinder having an interior, first and second ends and defining an axis, wherein the interior includes a damping fluid chamber and a damping piston movably mounted therein for movement between the first and second ends, wherein the damping piston is mounted on a first end of a shaft, wherein the first end of the shaft is movably retained within the interior of the first cylinder; first and second bypass openings configured for opening into the damping fluid chamber at first and second axially spaced-apart positions; a bypass channel fluidly coupling the first and second bypass openings; a fluid metering valve; and a floating piston dividing a portion of the shock absorber into a gas chamber and the reservoir chamber, wherein the fluid metering valve and the floating piston define the reservoir chamber there between.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of and claims the benefitof co-pending U.S. patent application Ser. No. 16/600,347, filed on Oct.11, 2019, entitled “SHOCK ABSORBER”, by John Marking et al., havingAttorney Docket No. FOX-P4-21-14-US.DIV.CON, and assigned to theassignee of the present application, and is hereby incorporated byreference in its entirety herein.

The application Ser. No. 16/600,347 is a continuation application of andclaims the benefit of U.S. patent application Ser. No. 16/246,217 filedon Jan. 11, 2019, Now U.S. Pat. No. 10,576,803, entitled “SHOCKABSORBER”, by John Marking et al., having Attorney Docket No.FOX-P4-21-14-US.DIV, and assigned to the assignee of the presentapplication, and is hereby incorporated by reference in its entiretyherein.

The application Ser. No. 16/246,217 is a divisional application of andclaims the benefit of U.S. patent application Ser. No. 14/488,894 filedon Sep. 17, 2014, Now U.S. Pat. No. 10,183,539, entitled “SHOCKABSORBER”, by John Marking et al., having Attorney Docket No.FOX-P4-21-14-US, and assigned to the assignee of the presentapplication, and is hereby incorporated by reference in its entiretyherein.

BACKGROUND Field of the Invention

The present invention relates to shock absorbers.

Description of the Related Art

Many types of suspensions and supports include a spring and a dampingdevice to help isolate that supported from the support structure orsurface. For example, automotive vehicles commonly use separate springsand simple shock absorbers to support the vehicle frame on the axleassemblies. Simple shock absorbers are typically oil-filled cylinderswithin which a vented piston is mounted. The piston is connected isconnected to a shaft which extends out of one end of the cylinder. Theouter end of the shaft is mounted to one point on the vehicle and theother end of the cylinder is mounted to another point on the vehicle inparallel with the suspension spring. Thus, simple shock absorbers onlyprovide damping and not support.

Another type of shock absorber, which is the type commonly used withmotorcycles, off-road vehicles, competition automotive vehicles andoff-road bicycles, combines both the suspension function and the shockabsorbing function in one unit. This second type of shock absorbercommonly uses a spring unit to provide the suspension function and iscoupled with a damping unit to provide the damping function.

Typical shock absorbers (also referred to as shocks) provide two kindsof damping: compression damping (“CD”), and rebound damping (“RD”). Onerefers to a damping force created during an “inward” travel of the shaft(shortening of the shock), the other refers to damping force createdduring an “outward” travel of the shaft (lengthening of the shock).Generally, but not always—depending on the linkage connecting the shockto the vehicle, RD applies during outward motion and CD applies duringinward motion. Some shocks are externally adjustable by the user toprovide for RD and/or CD adjustment.

Piston-type shock absorbers can be designed to provide the same amountof damping during both the compression stroke and the rebound stroke.Alternatively, the fluid passageways through the vented, damping pistoncan be designed so that the restriction to fluid flow through thedamping piston during the compression stroke is different than therestriction to fluid flow during the rebound stroke. In this case, thedamping during the entire compression stroke is different than thedamping during the entire rebound stroke.

Further, in a typical fluid operated damper, the damping fluid flow isinhibited by forcing fluid through a restrictive area or orifice, whicheffectively slows the movement of the damper during compression andrebound strokes.

During some instances of operation, conventional shock absorbers, andtherefore the vehicle rider, experience cavitation, during which theshaft of the shock absorber moves into the damping fluid chamber at itsfull travel length without providing any damping function. What isneeded is a simple solution for reducing cavitation in a shock absorber.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present invention are illustrated by way of example, andnot by way of limitation, in the accompanying drawings, wherein:

FIG. 1A is a side cross-sectional view of a concentric cylinder bypassdamper for positioning in the front of a vehicle and with the piston ina rest position prior to a beginning of a compression stroke, inaccordance with an embodiment.

FIG. 1B is a side perspective view of the concentric cylinder bypassdamper of FIG. 1A, in accordance with an embodiment.

FIG. 1C depicts an enlarged view of the concentric cylinder bypassdamper of FIG. 1A, in accordance with an embodiment.

FIG. 1D depicts an enlarged view of the concentric cylinder bypassdamper of FIG. 1C in a resting position, in accordance with anembodiment.

FIG. 1E depicts an enlarged view of the concentric cylinder bypassdamper of FIG. 1C, wherein a compression stroke is occurring and thedamping piston seal has passed some bypass openings, in accordance withan embodiment.

FIG. 1F depicts an enlarged view of the concentric cylinder bypassdamper of FIG. 1C, wherein a compression stroke is occurring and thedamping piston seal has passed some bypass openings, in accordance withan embodiment.

FIG. 1G depicts an enlarged view of the concentric cylinder bypassdamper of FIG. 1C, wherein a compression stroke is occurring and thedamping piston seal has passed all of the bypass openings, in accordancewith an embodiment.

FIG. 1H depicts a side cross-sectional view of the shock absorber ofFIG. 1A, in accordance with an embodiment.

FIG. 1I depicts the piston assembly of FIG. 1H, in accordance with anembodiment.

FIG. 1J depicts the fluid metering valve/floating piston assembly ofFIG. 1H, in accordance with an embodiment.

FIG. 1K depicts the set of bypass openings of FIG. 1H, in accordancewith an embodiment.

FIG. 2A depicts a perspective view of a concentric cylinder bypassdamper to be positioned in the rear of a vehicle and having a remotereservoir, in accordance with an embodiment.

FIG. 2B depicts a side view of a concentric cylinder bypass damper to bepositioned in the rear of a vehicle, wherein a portion of the side viewis a perspective view and another portion of the side view is across-sectional view showing springs therein, in accordance with anembodiment.

FIG. 2C depicts a cross-sectional side view of a concentric cylinderbypass damper to be positioned in the rear of a vehicle, in accordancewith an embodiment.

FIG. 2D depicts a side cross-sectional view of the shock absorber ofFIG. 2A, in accordance with an embodiment.

FIG. 2E depicts the piston assembly of FIG. 2D, in accordance with anembodiment.

FIG. 2F depicts the fluid metering valve/floating piston assembly ofFIG. 2D, in accordance with an embodiment.

FIG. 2G depicts the set of bypass openings of FIG. 2D, in accordancewith an embodiment.

FIG. 3A depicts a side perspective view of a shock absorber, having anair spring and a concentric cylinder bypass damper, in accordance withan embodiment.

FIG. 3B depicts a side cross-sectional view of a shock absorber, havingan air spring and a concentric cylinder bypass damper, in accordancewith an embodiment.

FIG. 3C depicts a top perspective view of the shock absorber of FIG. 3A,showing a fitting, in accordance with an embodiment.

FIG. 3D depicts a side perspective view of the fitting of FIG. 3C, inaccordance with an embodiment.

FIG. 3E depicts a side cross-sectional view of a shock absorber, inaccordance with an embodiment.

The drawings referred to in this description should be understood as notbeing drawn to scale except if specifically noted.

DESCRIPTION OF EMBODIMENTS

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various embodiments of thepresent invention and is not intended to represent the only embodimentsin which the present invention may be practiced. Each embodimentdescribed in this disclosure is provided merely as an example orillustration of the present invention, and should not necessarily beconstrued as preferred or advantageous over other embodiments. In someinstances, well known methods, procedures, objects, and circuits havenot been described in detail as not to unnecessarily obscure aspects ofthe present disclosure.

Overview of Discussion

Example shock absorbers that provide various degrees of damping aredescribed herein. Discussion begins with a description of embodiments ofthe present technology, and more particularly, concentric cylinderbypass dampers. See FIGS. 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I, 1J and 1K(a front shock absorber) and FIGS. 2A, 2B, 2C, 2D, 2E, 2F and 2G (a rearshock absorber). Following, a shock absorber that includes theconcentric cylinder bypass damper integrated with an air spring isdescribed. See FIGS. 3A, 3B, 3C, 3D, and 3E.

Example Concentric Cylinder Bypass Damper

FIGS. 1A-1K depict a concentric cylinder bypass damper of a shockabsorber, in accordance with embodiments, for positioning in the frontsuspension system of a vehicle. More particularly and as will bedescribed herein, FIG. 1A is a side cross-sectional view of a shockabsorber with a piston in a rest position prior to a beginning of acompression stroke, in accordance with an embodiment. FIG. 1B is a sideperspective view of the shock absorber of FIG. 1A, in accordance with anembodiment.

FIG. 1C is an enlarged view of the concentric cylinder bypass damper 48of the shock absorber 2 of FIG. 1A, in accordance with an embodiment.The concentric cylinder bypass damper 48 includes a cylinder 12 havingan interior 28, first and second ends, 38 and 10, respectively, anddefining an axis 16. A floating piston 6 and a fluid metering valve 8divide the interior 28 into a damping fluid chamber 14 and a gas chamber4. The gas chamber 4, the floating piston 6 and the fluid metering valve8 accommodate the volume of oil or other damping fluid within thedamping fluid chamber 14 that is displaced by the movement of the shaft40 into the damping fluid chamber 14. In other words, when the shaft 40moves into the damping fluid chamber 14, some of the fluid within thedamping fluid chamber 14 is displaced and travels through the fluidmetering valve 8 and into the reservoir chamber 46 that is positionedbetween the fluid metering valve 8 and the floating piston 6. The morefluid that enters the reservoir chamber 46, the more that the floatingpiston 6 is pushed into the gas chamber 4, such that the gas within thegas chamber 4 becomes more compressed than was its state without theentry of the floating piston 6 into the gas chamber 4. The compressionof the gas within the gas chamber 4 is suggested by the arrows 42C-42Gin FIGS. 1A-1G.

Of note, while FIGS. 1C-1J show a fluid metering valve (fluid meteringvalve 8) having a particular set of components that will be explainedbelow, it should be appreciated that the fluid metering valve mayinclude one or more valves, having a different structure than that shownwith respect to the fluid metering valve 8, that regulate fluid movingthere through, thereby facilitating a damping effect. In one embodiment,and as shown, the fluid metering valve 8 is positioned adjacent to thefloating piston 6. The fluid metering valve 8, in one embodiment,includes a compression piston 60, a shaft 70 and a set of shim stacks 62that removably cover one or more passages 66 through the compressionpiston 60. For example, and with reference to FIG. 1C, as the shaft 40moves into the damping fluid chamber 14, the damping fluid moves throughthe or more passages 66 within the compression piston 60 and past theshim stack 62 covering the one or more passages 66, into the reservoir46. The shim stack 62 deflects about the spacer 68 and moves toselectively open the one or more passages 66.

Of note, the seal member 64 adjacent to the floating piston 6 provides asubstantially fluid tight seal between the floating piston 6 and theinterior surface of the cylinder 12. In one embodiment, the seal member64 is an annular seal having a substantially square cross-section.However, other suitable seals may also be used.

A damping piston 34 is moveably mounted within the cylinder 12 formoving between the first and second ends, 38 and 10, respectively, ofthe cylinder 12. A number of axially separated bypass openings 18, 20,22, 24 and 26 are formed through the cylinder 12. Of note, there may bemore or less bypass openings than those described as bypass openings 18,20, 22, 24 and 26. A bypass cylinder 30 surrounds the cylinder 12 anddefines a cylindrical bypass channel 32 there between. In oneembodiment, all of the bypass openings are open 18, 20, 22, 24 and 26,which enables the same damping characteristics to occur along the samesegment of the stroke, whether the stroke is the compression stroke orthe rebound stroke. The bypass openings 18, 20, 22, 24 and 26 that areopen fluidly couple the damping fluid chamber 14 and the cylindricalbypass channel 32 to permit some damping fluid to bypass the dampingpiston 34 when the damping piston 34 is positioned between these bypassopenings 18, 20, 22, 24 and 26, thus reducing the damping effect duringthis portion of the stroke. In other embodiments, some of the bypassopenings 18, 20, 22, 24 and 26 are always open, while other bypassopenings of the bypass openings 18, 20, 22, 24 and 26 have expandablebands positioned within annular grooves formed in the outer surface ofthe cylinder 12, such as those expandable bands and annular groovesshown in U.S. Pat. No. 6,415,895, POSITION-SENSITIVE SHOCK ABSORBER, byMarking et al., assigned to Fox Factory, Inc., and incorporated hereinin its entirety by reference thereto. In this situation, the expandablebands block the bypass openings. The expandable bands permit fluid flowfrom the damping fluid chamber 14 to the cylindrical bypass channel 32,but restrict, and typically prevent, fluid flow in the oppositedirection. Thus, the shock absorber 2 will exhibit different dampingcharacteristics along the same segment of the stroke depending uponwhether the stroke is a compression stroke or a rebound stroke.

FIG. 1D illustrates an enlarged view of FIG. 1C, in accordance with anembodiment, wherein the damping piston 34 is at rest adjacent to thefirst end 38 of the cylinder 12. The movement of the damping piston 34upwardly, that is in the compression stroke, is dampened only by theflow of damping fluid through the damping piston 34, until the dampingpiston seal 36, which contacts and seals against the interior 28 of thecylinder 12, passes the bypass opening 26. When this occurs, fluid flowcan be both through the damping piston 34, which is vented (see arrowsdepicting fluid moving through the damping piston 34), and also canbypass the damping piston 34 through the bypass openings 18, 20 and 22,along the bypass channel 32 and back through the bypass openings 24 and26, as is illustrated in FIG. 1E, in accordance with an embodiment (Seearrows 44 of FIG. 1E). This 3/2 zone (a flow through 3 bypass openingsand 2 bypass openings on either side of the damping piston 34) providesthe softest (least amount of damping) zone of the compression stroke.

The next zone of the compression stroke is created when the dampingpiston seal 36 covers the bypass opening 22 as shown in FIG. 1F. This2/2 zone of the compression stroke is still soft, but not as soft asthat shown in FIG. 1E. Some fluid flows through the damping piston 34and also bypasses the damping piston 34 through the bypass openings 18and 20, through the cylindrical bypass channel 32 and out the bypassopenings 24 and 26 into the chamber below the damping piston 34 (Seearrows 44 of FIG. 1F). The 2/2 zone of FIG. 1F continues until thebypass opening 20 is covered by the damping piston seal 36. This createsa short 1/2 zone (not illustrated) until the damping piston seal 36covers the bypass opening 20. Continued compression stroke movement,wherein the damping piston seal 36 passes or covers bypass opening 18,shown in FIG. 1G, results in a 0/0 zone (no fluid bypasses the dampingpiston 34). As shown by the arrows 44 of FIG. 1G, the fluid flowsthrough the damping piston 34.

The rebound stroke, not shown, exhibits no bypass fluid flow (a 1/1zone) until the damping piston seal 36 passes the bypass opening 18. Atthis point, the fluid flow is out through the bypass openings 22, 24 and26 (bypass opening 20 being covered by the damping piston seal 36) andback in through the bypass opening 18 for a 3/1 zone. After the dampingpiston seal 36 passes the bypass opening 20, the bypass zone becomes a3/2 zone (or remains 3/1 if, for example, a flow valve is positioned atthe bypass opening 20). Once the damping piston seal 36 covers thebypass opening 22, the bypass zone is a 2/2 zone until the dampingpiston seal 36 covers the bypass opening 24. With the bypass opening 24covered but the bypass opening 26 open, the fluid can pass through thebypass openings 26, leaving a 1/4 zone. Once the damping piston seal 36covers the bypass opening 26, no bypass occurs, and is a 0/0 zone.

Thus, it is seen that the amount of the damping fluid bypass variesalong both the compression and rebound strokes and may be differentalong the same segments of the cylinder on the compression and reboundstrokes.

Conceptually, the damping piston (referred to heretofore, as “venteddamping piston”) could by non-vented (solid) with all the damping fluidchanneled through the bypass openings or vented, wherein the dampingfluid passes there through.

As indicated above, according to embodiments, the fluid metering valvemay include any valve (or valves) structure that is capable ofrestricting a flow of fluid through one or more passageways that aredisposed within one or more pistons, wherein this valve structure(s)includes one or more shim stacks that removably block/seal the one ormore passageways. As noted and according to embodiments, the fluidmetering valve, as shown with respect to the fluid metering valve 8shown in FIGS. 1C-1J, is positioned between the damping fluid chamber 14and the floating piston 6 of the concentric cylinder bypass damper 48 ofa shock absorber 2.

With reference now to FIG. 1E, it can be seen that the damping piston34, attached to the shaft 40, is entering the interior 28 of thecylinder 12, thereby pushing its way into the damping fluid chamber 14.The fluid within the damping fluid chamber 14 is compressed due to theentry of the shaft 40 into the damping fluid chamber 14. As describedherein, due to the pressure on the fluid caused by the entry of theshaft 40 into the damping fluid chamber 14, damping fluid flows from oneside of the damping piston 34 to the other side of the damping piston34, through both the damping piston 34 and the cylindrical bypasschannel 32.

In a situation in which a compression of a shock absorber occurs veryquickly, the fast movement of the fluid through the channels of thedamping piston and/or the bypass openings may cause a cavitation tooccur. However, features of the present technology reduce cavitation andits effects during the compression and rebound of a shock absorber thatinclude a structure that distributes the flow of the fluid, through adamping piston that may be vented, through various bypass openings, andthrough a fluid metering valve.

For example, a first pressure drop occurs through the flow of a portionof the fluid through the damping piston 34 and/or through one or morebypass openings 18, 20, 22, 24 and 26. A second pressure drop occursthrough the flow of fluid through the fluid metering valve 8 and intothe reservoir chamber 46. A further source of pressure drop is caused bythe floating piston 6 moving toward the gas chamber 4 in response to theincreased pressure within the reservoir chamber 46 caused by themovement of fluid therein. Thus, because the pressure drop is enabledvia embodiments described herein, the likelihood of the vehicle riderexperiencing cavitation effects is reduced. Additionally, at high enoughvelocities, any cavitation that occurs will be of a reduced magnitudeversus a standard conventional signal pressure drop flow regime.

With reference now to FIGS. 1D-1G, the fluid flow through the concentriccylinder bypass damper 48 is explained, in accordance with embodiments.As seen in FIG. 1D, the damping piston 34 is shown at rest adjacent tothe first end 38 of the cylinder 12. In this position, the floatingpiston 6 remains at rest and adjacent to the fluid metering valve 8,with the reservoir chamber 46 there between.

However, as shown in FIG. 1E, when the shaft 40, during a compressionstroke, moves upward into the interior 28 of the cylinder 12, thedamping piston 34, which is attached to the shaft 40, also moves upwardsinto the interior 28 of the cylinder 12. The upward movement of thedamping piston 34 causes, in one embodiment and as described herein, thedamping fluid to flow through the bypass openings, such as bypassopenings 18, 20, 22, 24 and 26, from the interior 28 above the dampingpiston 34, through the cylindrical bypass channel 32, and into theinterior 28 below the damping piston 34. In another embodiment, thedamping fluid not only flows through the bypass openings, but alsothrough the damping piston 34, which is vented. Sometimes, the force ofan impact upon the vehicle, which is translated to the concentriccylinder bypass damper 48, causes the shaft 40, and hence also thedamping piston 34 to move upwards into the interior 28 of the cylinder12 at such a velocity that the bypass openings and the damping piston 34that is vented do not create enough passageways for the damping fluid tobecome dispersed quickly enough to reduce the damping effect of theconcentric cylinder bypass damper 48, as well as provide enoughdispersal of the damping fluid such that cavitation is avoided. A ridethat is softer than what the bypass openings and the damping piston 34that is vented can provide is desired.

Embodiments of the present technology provide a third fluid dispersalmechanism, in addition to the bypass openings and the damping piston(that, one embodiment, is vented). Embodiments provide a reservoirchamber 46 in fluid communication with the damping fluid chamber 14, viaa fluid metering valve 8. A floating piston 6 is slidably engaged withthe inner surface of the cylinder 12 and separates the reservoir chamber46 from the gas chamber 4. In other words, the floating piston 6 ismounted on the inner surface of the cylinder 12 such that it may slideup and down the cylinder 12 while remaining in a position between thereservoir chamber 46 and the gas chamber 4.

In operation, in one embodiment and with reference to FIG. 1E, theconcentric cylinder bypass damper 48 is compressed such that theinterior 28 of the cylinder 12 experiences the entry of a portion of theshaft 40 and the damping piston 34 therein. The entry of the portion ofthe shaft 40 and the damping piston 34 occurs at such a rate that thedamping fluid within the damping fluid chamber 14 is displaced andpushed through the bypass openings, the vents through the damping piston34, and the passageways through the fluid metering valve 8. Thus, aportion of the damping fluid moves from the damping fluid chamber 14,through the fluid metering valve 8, and into the reservoir chamber 46.By enabling the floating piston 6 to move (slide) upwards into the gaschamber 4, the floating piston 6 and the gas chamber 4 are able toaccommodate the volume of the oil or other damping fluid displaced intothe reservoir chamber 46. Arrows 42E show that the dimensionmeasurements of the gas chamber 4 at FIG. 1E are smaller (when the shaft40 and the damping piston 34 have moved upwards into the interior 28 ofthe cylinder 12) than the dimension measurements of the gas chamber 4 ofFIG. 1D (shown by arrows 42D) when the shaft 40 and the damping piston34 are at rest. In other words, the gas chamber 4 of FIG. 1E is morecompressed than that gas chamber 4 shown in FIG. 1D, due to the entry ofthe shaft 40 and damping piston 34 into the interior 28 of the cylinder12.

FIG. 1F shows a further entry of the shaft 40 and the damping piston 34into the interior 28 of the cylinder 12. More damping fluid has movedfrom the damping fluid chamber 14 and to the reservoir chamber 46 (aswell as the interior 28 of the cylinder 12 that is below the dampingpiston 34). FIG. 1F also shows that the gas chamber 4 has continued tocompress (as compared to the compression of the gas chamber 4 shown atFIG. 1E) as the floating piston 6 continues to move upwards. Thefloating piston 6 is being pushed by the damping fluid that wasdisplaced from the damping fluid chamber 14 and into the reservoirchamber 46.

FIG. 1G shows a further entry of the shaft 40 and the damping piston 34into the interior 28 of the cylinder 12. More damping fluid has movedfrom the damping fluid chamber 14 and to the reservoir chamber 46 (aswell as the interior 28 of the cylinder 12 that is below the dampingpiston 34). FIG. 1G also shows that the gas chamber 4 has continued tocompress (as compared to the compression of the gas chamber 4 shown atFIG. 1F) as the floating piston 6 continues to move upwards. Thefloating piston 6 is being pushed by the damping fluid that wasdisplaced from the damping fluid chamber 14 and into the reservoirchamber 46.

Thus, the fluid metering valve 8 provides an added dispersal mechanismby which the damping fluid within the damping fluid chamber 14 may bedisplaced, upon the entry of the shaft 40 and the damping piston 34 intothe interior 28 of the cylinder 12. The fluid metering valve 8 thus,through the dispersal of a further portion of the damping fluid fromwithin the damping fluid chamber 14, softens the vehicle ride by furtherreducing the damping provided by the shock absorber 2, and reduces thepossibility of cavitation. Additionally, the ability of the floatingpiston 6 to move and compress the gas chamber 4 and thereby accommodatethe volume of oil or other damping fluid within the reservoir chamber46, further softens the vehicle ride by further reducing the dampingprovided by the shock absorber 2, and thus further reducing thepossibility of cavitation.

FIG. 1H depicts a side cross-sectional view of the shock absorber ofFIG. 1A, in accordance with an embodiment. The shock absorber 2 includesthe concentric cylinder bypass damper 48. The concentric cylinder bypassdamper 48 is shown to include the piston assembly 50 (See FIG. 1I), thefluid metering valve/floating piston assembly 52 (See FIG. 1J) and theset of bypass openings 54 (See FIG. 1K).

FIG. 1I depicts the piston assembly 50 of FIG. 1H, in accordance with anembodiment. The piston assembly 50, including the damping piston 34 andthe damping piston seal 36 is integrated with the shaft 40.

FIG. 1J depicts the fluid metering valve/floating piston assembly 52 ofFIG. 1H, in accordance with an embodiment. The fluid meteringvalve/floating piston assembly 52 includes the fluid metering valve 8and the floating piston 6, sandwiching the reservoir chamber 46.

FIG. 1K depicts a set of bypass openings 54 of FIG. 1H, in accordancewith an embodiment.

FIGS. 2A-2C illustrate a shock absorber for positioning in a rear of avehicle, in accordance with embodiments. More particularly, FIG. 2Adepicts a perspective view of a shock absorber 200 to be positioned inthe rear of a vehicle, showing a remote reservoir 202 connected to themain body 204 of the shock absorber 200, in accordance with anembodiment.

FIG. 2B depicts a side view of the main body 104 of the shock absorber200 to be positioned in the rear of a vehicle, wherein a portion of theside view is a perspective view and another portion of the side view isa cross-sectional view showing springs 206 therein, in accordance withan embodiment.

FIG. 2C depicts a cross-sectional side view of the main body 204 and thereservoir 202 of the shock absorber 200 to be positioned in the rear ofa vehicle, in accordance with an embodiment. Of note, the springs 206that are shown in FIG. 2B are not shown in FIG. 2C. However, it shouldbe appreciated that the main body 204 includes a set of springs therein.The shock absorber 200 operates as both a suspension spring and as adamper. The spring may be an air spring arrangement, coil springs, orother suitable arrangements. The shock absorber 200 primarily includesan air sleeve 226, a concentric cylinder bypass damper 234 and areservoir 202. The concentric cylinder bypass damper 234 and thereservoir 202 are connected via connection 254. In one embodiment, theconnection 254 may be a hydraulic hose that physically connects the mainbody 204 of the shock absorber 200 to the reservoir 202. However, inanother embodiment, the reservoir 202 may also be directly connected tothe main body 204 of the shock absorber 200, such as being integrallyconnected to, or monolithically formed with, the air sleeve 226.

The concentric cylinder bypass damper 234 of the shock absorber 200includes a cylinder 238 having an interior 246, first and second ends,228 and 236, respectively, and defining an axis 244.

The reservoir 202 includes a fluid metering valve 208, a reservoirchamber 210, a floating piston 212 and a gas chamber 214. The fluidmetering valve 208 is positioned adjacent to the connection 254. Thereservoir chamber 210 is positioned between the fluid metering valve 208and the floating piston 212. The floating piston 212 is positionedbetween the reservoir chamber 210 and the gas chamber 214. The gaschamber 214, the floating piston 212, the reservoir chamber 210 and thefluid metering valve 208 accommodate the volume of oil or other dampingfluid that is displaced from the damping fluid chamber 230, caused bythe movement of the shaft 40 and the damping piston 218 into the dampingfluid chamber 14. The damping fluid is pushed through the connection 254and into the fluid metering valve 208. From the fluid metering valve208, the damping fluid is pushed into the reservoir chamber 210. As thevolume of damping fluid increases in the reservoir chamber 210, thefloating piston 212 is pushed into the gas chamber 214. Thus, the entryof the shaft 224 and the damping piston 218 into the damping fluidchamber 230 causes, amongst other events, the floating piston 212 tocompress the gas chamber 215 by sliding within the reservoir 202 towardsthe gas chamber 214.

It should be appreciated that the components within the concentriccylinder bypass damper 234 of the (rear) shock absorber 200 operate in asimilar manner to those components of the (front) shock absorber 2. Forexample, the concentric cylinder bypass damper 234 further includes adamping piston 218 that is vented and that is moveably mounted withinthe cylinder 238 for moving between the first and second ends, 228 and236, respectively, of the cylinder 238. A number of axially separatedbypass openings 240 and 242 are formed through the cylinder 238. Ofnote, there may be more or less bypass openings than that described asbypass openings 240 and 242. A bypass cylinder 222 surrounds thecylinder 238 and defines a cylindrical bypass channel 216. In oneembodiment, all of the bypass openings 240 and 242 are open, whichenable the same damping characteristics along the same segment of thestroke, whether the stroke is the compression stroke or the reboundstroke. The bypass openings 240 and 242 that are open fluidly couple thedamping fluid chamber 230 and the cylindrical bypass channel 216 topermit some damping fluid to bypass the vented damping piston 218 whenthe vented damping piston 218 is positioned between these bypassopenings 240 and 242, thus reducing the damping during this portion ofthe stroke. In other embodiments, some of the bypass openings 240 and242 are always open, while other bypass openings of the bypass openings240 and 242 have expandable bands positioned within annular groovesformed in the outer surface of the cylinder 238, such as thoseexpandable bands and annular grooves shown in U.S. Pat. No. 6,415,895,POSITION-SENSITIVE SHOCK ABSORBER, by Marking et al., assigned to FoxFactory, Inc., and incorporated herein in its entirety by referencethereto. In this situation, the expandable bands that block the bypassopenings act as check valve elements. The check valve elements permitfluid flow from the damping fluid chamber 230 to the cylindrical bypasschannel 216 but restrict, and typically prevent, fluid flow in theopposite direction. Thus, the shock absorber 200 will exhibit differentdamping characteristics along the same segment of the stroke dependingupon whether the stroke is the compression stroke or the rebound stroke.

FIG. 2D depicts a side cross-sectional view of the shock absorber 200 ofFIG. 2A, in accordance with an embodiment. The shock absorber 200includes the main body 204 and the reservoir 202. The main body 204includes the concentric cylinder bypass damper 234 slidably integratedwith the air sleeve 226. The concentric cylinder bypass damper 234includes the piston assembly 248 (See FIG. 2E) and the set of bypassopenings 252 (See FIG. 2G). The reservoir 202 includes the fluidmetering valve/floating piston assembly 250 (See FIG. 2F).

FIG. 2E depicts the piston assembly 248 of FIG. 2D, in accordance withan embodiment. The piston assembly 248 includes the damping piston 218and the damping piston seal 220 slidably integrated with the shaft 224).

FIG. 2F depicts the fluid metering valve/floating piston assembly 250 ofFIG. 2D, in accordance with an embodiment. The fluid meteringvalve/floating piston assembly 250 includes the fluid metering valve 208and the floating piston 212, sandwiching the reservoir chamber 210.

FIG. 2G depicts the set of bypass openings 252 of FIG. 2D, in accordancewith an embodiment.

Example Air Spring Integrated with Concentric Cylinder Bypass Damper

Embodiments of the present technology include the concentric cylinderbypass damper 48 or the concentric cylinder bypass damper 234 integratedwith an air spring, as will be described herein. Referring now to FIG.3A, a side perspective view of a shock absorber 300, having an airspring with a concentric cylinder bypass damper therein, in accordancewith an embodiment.

More particularly, and with reference to FIG. 3B, a side cross-sectionalview of the shock absorber 300 of FIG. 3A is shown, having the airspring 302 with a concentric cylinder bypass damper 312 slidably engagedtherein, in accordance with an embodiment. As shown, the air spring 302includes the air spring chamber 306 and the shaft 308. A fitting 304 isdisposed at the top of the air spring 302. The fitting 304 is configuredfor enabling an entry of air into the air spring chamber 306.

The air spring chamber 306 has only air within, in one embodiment. Ascompression of the shock absorber 300 occurs, the concentric cylinderbypass damper 312 moves further into the air spring chamber 306 of theair spring 302. As the concentric cylinder bypass damper 312 movesfurther into the air spring chamber 306, the shaft 308 moves furtherinto the damping fluid chamber 314 of the concentric cylinder bypassdamper 312. As noted herein, in one embodiment, the concentric cylinderbypass damper 312 is the concentric cylinder bypass damper 2, while inanother embodiment, the concentric cylinder bypass damper 312 is theconcentric cylinder bypass damper 234. As such, the damping fluidchamber 314 operates in one embodiment as the damping fluid chamber 14,while in another embodiment, operates as the damping fluid chamber 230.

Upon the movement of the concentric cylinder bypass damper 312 into theair spring chamber 306, a damping effect occurs. The strength of thedamping effect is determined by the amount of air pressure that iswithin the air spring chamber 306. As the concentric cylinder bypassdamper 312 enters the air spring chamber 306 the volume of the airspring chamber 306 is increased. The air within the air spring chamber306 provides the resistance to the movement of the concentric cylinderbypass damper 312 therein.

FIG. 3C is a top perspective view of the shock absorber of FIG. 3A,showing the fitting 304, in accordance with an embodiment. FIG. 3D is aside perspective view of the fitting 304 of FIG. 3A, in accordance withan embodiment.

Thus, the shock absorber 300 of FIGS. 3A-3D provides the concentriccylinder bypass damper 312, which enables a damping effect to occur,coupled with the air spring 302, which enables a further damping effectto occur. The damping effect can be tuned by increasing or decreasingany of, but not limited to, the following: air pressure within the airspring chamber 306; size of the air spring chamber 306 within the airspring 302; number and placement of bypass openings within theconcentric cylinder bypass damper 312; and amount of fluid allowed toflow through the fluid metering valve 316 (via various configurations ofthe fluid metering valve 316). Of note, the fluid metering valve 316 inone embodiment is the fluid metering valve 8, while in anotherembodiment, the fluid metering valve 316 is the fluid metering valve208.

FIG. 3E depicts a side cross-sectional view of a shock absorber 318, inaccordance with an embodiment. The shock absorber 318 includes all ofthe components of the shock absorber 300 described herein. Additionally,the air spring 302 of the shock absorber 318 of FIG. 3E also includes aset of coiled springs configured for reducing the speed of thecompression of the concentric cylinder bypass damper 312 into the airspring chamber 306. The set of coiled springs may include one or morelengths of coiled springs, one or more types of coiled springs and oneor more sizes of coiled springs. The set of coiled springs is disposedwithin the air spring chamber 306 such that upon the compression of theshock absorber 318, the coiled springs are positioned to provideresistance to the concentric cylinder bypass damper 312 from enteringthe air spring chamber 306.

For example, and with reference to FIG. 3E, the first coiled spring 320and the second coiled spring 322 are positioned in series with eachother, and separated by the coiled spring separator 324.

The first end 330 of the first coiled spring 320 is positioned at thefirst end 326 of the air spring chamber 306. The second end 332 of thefirst coiled spring 320 is positioned against the first surface 338 ofthe coiled spring separator 324.

The first end 334 of the second coiled spring 322 is positioned againstthe second surface 340 of the coiled spring separator 324. The secondend 336 of the second coiled spring 322 is positioned at the second end328 of the air spring chamber 306.

The first coiled spring 320, in one embodiment, is longer in length, andis greater in compressive strength than the second coiled spring 322.Thus, the placement and the disposition of the first coiled spring 320provide resistance to the expansion of the second coiled spring 322toward the first coiled spring 320.

The coiled spring separator 324 provides a mechanism by which the firstcoiled spring 320 may engage with the second coiled spring 322,regardless of each coiled spring's length, type, and size. The diameterof the coiled spring separator 324 is larger than the diameter of eitherthe first coiled spring 320 or the second coiled 322, measured from theouter edges of the first coiled spring 320 and the second coiled spring322. Thus, in operation, the second end 332 of the first coiled spring320 pushes against the first surface 338 of the coiled spring separator324 and the first end 334 of the second coiled spring 322 pushes againstthe second surface 340 of the coiled spring separator 324.

The placement of the first coiled spring 320 and the second coiledspring 322 does not interfere with the sliding movement of theconcentric cylinder bypass damper 312 within the air spring chamber 306.The diameter of the first coiled spring 320, measured from its inneredge, is greater than the diameter of the concentric cylinder bypassdamper 312, such that the concentric cylinder bypass damper 312 may movewithin the interior area of the first coiled spring 320 without touchingthe first coiled spring 320.

Upon compression of the shock absorber 318, the concentric cylinderbypass damper 312, moves further into the air spring chamber 306. Uponfurther compression of the shock absorber 318, the concentric cylinderbypass damper 312 moves further into the air spring chamber 306. In oneembodiment, upon a continued compression of the shock absorber 318, thetop surface 342 of the concentric cylinder bypass damper 312 pushesagainst the first surface 338 of the coiled spring separator 324 (theconcentric cylinder bypass damper 312 pushes against the coiled springseparator 324). When the concentric cylinder bypass damper 312 pushesagainst the coiled spring separator 324, the second surface 340 pushesagainst the first end 334 of the second coiled spring 322. The secondcoiled spring 322 provides resistance to the movement of the coiledspring separator 324 in its direction.

Thus, the combination of the first coiled spring 320 and the secondcoiled spring 322 engaged with the coiled spring separator 324 providesa further source of damping. In addition to the operation of the coiledsprings and as described herein, the air within the air spring chamber306 provides yet another source of tunable damping for the shockabsorber 318.

It should be noted that any of the features disclosed herein may beuseful alone or in any suitable combination. While the foregoing isdirected to embodiments of the present invention, other and furtherembodiments of the invention may be implemented without departing fromthe scope of the invention, and the scope thereof is determined by theclaims that follow.

What we claim is:
 1. A shock absorber comprising: a cylinder having aninterior and a cylindrical axis, said cylinder having a first end and asecond end, said first end disposed separated from said second end alongsaid cylindrical axis, wherein said interior comprises a damping fluidchamber and a damping piston, said damping piston mounted on a first endof a shaft, wherein said first end of said shaft is retained within saidinterior of said cylinder and movable along at least a portion of saidcylindrical axis such that said damping piston is movable within saidinterior of said cylinder between said first end and said second end; afirst bypass opening configured for opening into said damping fluidchamber at a first axial position of said cylinder; a second bypassopening configured for opening into said damping fluid chamber at secondaxial position of said cylinder, said first axial position and saidsecond axial position being spaced apart from each; a bypass channelfluidly coupling said first bypass opening and said second bypassopening; a reservoir chamber; a gas chamber; a floating piston disposedseparating said gas chamber and said reservoir chamber; a fluid meteringvalve disposed to meter fluid flow between said damping fluid chamberand said reservoir chamber during at least one of a compression strokeof said shock absorber and a rebound stroke of said shock absorber, saidfluid metering valve and said floating piston defining said reservoirchamber there between; and an air spring.